If passages for a cooling fluid are to be integrated in a housing made of metal casting, e.g., for an alternator, two methods for producing them are known. On the one hand, the housing can be produced using the sand-casting method with an appropriate core. This is expensive for series production in particular. On the other hand, the housing can be produced in two parts using the diecasting method—if the geometry allows this—whereby the two housing parts must then be interconnected in sealed fashion. This is expensive as well.